While it's true that bacteria stop multiplying below 32°F (0°C), they do not die. If you put a bacteria laden piece of food in the freezer, it'll be the same bacteria laden piece of food when you take it out to thaw. Among the bacteria that can tolerate extreme cold are Arthrobacter sp., Psychrobacter sp. and members of the genera Halomonas, Pseudomonas, Hyphomonas, and Sphingomonas. Another example is Chryseobacterium greenlandensis, a psychrophile that was found in 120,000-year-old ice. Psychrophiles, literally “cold lovers,” are organisms adapted to live at extremely cold temperatures. These are single-celled life forms, most often bacteria, but also blue green algae, yeasts, and fungi that can grow at temperatures as low as -13 degrees

Bacteria can live in hotter and colder temperatures than humans, but they do best in a warm, moist, protein-rich environment that is pH neutral or slightly acidic. There are exceptions, however. Some bacteria thrive in extreme heat or cold, while others can survive under highly acidic or extremely salty conditions. Psychrophiles, literally “cold lovers,” are organisms adapted to live at extremely cold temperatures. These are single-celled life forms, most often bacteria, but also blue green algae, yeasts, and fungi that can grow at temperatures as low as -13 degrees.Cold shock proteins aid the bacteria to survive in temperatures lesser than the optimum temperature and the heat shock proteins make bacteria survive in temperatures greater than the optimum growth temperature. This is achieved due to organization of prokaryotic nuclei and condensation of chromosomes. Bacteria can live in hotter and colder temperatures than humans, but they do best in a warm, moist, protein-rich environment that is pH neutral or slightly acidic. There are exceptions, however. Some bacteria thrive in extreme heat or cold, while others can survive under highly acidic or extremely salty conditions. The microorganisms live in every part of the biosphere, and some of them are even capable of growing at low temperatures, including those below the freezing point. Some pathogens will grown between 0°C and 20°C but they multiply more slowly at the lower temperatures. The lowest recorded temperature for the growth of pathogenic bacteria is -2°C and although pathogens can survive freezing they do not multiply. The nematode Panagrolaimus davidi occurs mainly along the coast of Antarctica, and can withstand temperatures as low as -80°C. It is one of the few organisms that can survive the freezing of its internal tissues.

Some bacteria thrive in extreme heat or cold, while others can survive under highly acidic or extremely salty conditions. Water expands as it freezes, and the resultant pressure causes the cell to burst. Bacteria can live in hotter and colder temperatures than humans, but they do best in a warm, moist, protein-rich environment that is pH neutral or slightly acidic. There are exceptions, however. Even if a cell manages to remain intact as it freezes, the cell membrane can still be punctured by microscopic ice crystals as the organism thaws out. To protect themselves from these effects, many microbes produce antifreeze proteins. The low temperatures cause a delay in chemical reactions in food, which results in slowing down or causing bacteria to become dormant. The bacteria are still alive but they stop growing or producing toxins so in effect pausing reactions. Some of these microbes were found to have adapted in special ways to survive in the snow and ice. These microbes are called psychrophiles, which means “cold-loving” in Greek. Psychrophiles are largely bacteria but can also include other microbes. Microbes cannot survive in solid ice. Water expands as it freezes, and the resultant pressure causes the cell to burst. Even if a cell manages to remain intact as it freezes, the cell membrane can still be punctured by microscopic ice crystals as the organism thaws out. To protect themselves from these effects, many microbes produce antifreeze proteins. Most bacteria thrive at 40 to 140 degrees Fahrenheit, which is why it's important to keep food refrigerated or cook it at high temperatures. Freezing temperatures don't kill germs, but it makes them dormant until they are thawed. Among the bacteria that can tolerate extreme cold are Arthrobacter sp., Psychrobacter sp. and members of the genera Halomonas, Pseudomonas, Hyphomonas, and Sphingomonas. Another example is Chryseobacterium greenlandensis, a psychrophile that was found in 120,000-year-old ice.